What effect do keystone species have on an ecosystem? apex

Plz plz plz quick! 49 points for whoever which of the following statements about greenhouse effect is true? *life on earth is suffering because of greenhouse effect *the greenhouse effect is caused by human activity *all greenhouse gases are harmful *life on earth would not exist without the greenhouse effect

What is the significance of the protein-lined pits? a. protein attracts other proteins needed for atp synthesis within the cell. b. protein-lined pits are able to transport one molecule at a time down the concentration gradient within the cell. c. the polarity of proteins allows other polar molecules to attach and be transported in the cell by transport channels. d. receptors within the pits allow ligands to fuse and be transported into the cell by endocytosis.

Do the following statements describe actin, myosin, both of the proteins or neither of the proteins? (a) contains a binding site for calcium (b) found in the i band (c) exists in a globular (g) form and a filamentous (f) form (d) contains a binding site for atp (e) is a component of the thin filament (f) is a component of the thick filament